Water-meter frost bolt



J. THOMSON WATER METER FROST BOLT Filed Feb. 15 1923 INVENTORZ j and thedisc chamber term, frost-bolt,

bot-tom.

Patented Jan. 20, 1925.

JOHN THOMSON, BROOKLYN, YORK.

WATER-METER raosr Bom'.

I Application filed February 15, 1923. Serial No. 619,214.

To all whom it may concern:

Be it known that I, JOHN THoMsoN, a citizen of the United States, and aresident of the borough of Brooklyn, city and State of New York, haveinvented a VVater-Meter Frost Bolt, of which the following is aspecificatio This invention relates to. water meters, particularlyconsisting in means, empirically termed a frost-bolt, for preventing theoperative parts of meters from being damaged When water therein ispartially or wholly frozen, and also to avoid'damaging the functioningmeans itself. 7 The. said is a unitary expression like that of the nowcommon trade nomenclature, such as frost-bottom, or frostprotector.

' It is believed that of the prior and existing state of the art willhere sufiice. The present applicant was the original designerandexploiter of the disc water meter known'by the trade-name of Trident,in which the discv casing was formed oftwo parts provided with ahorizontal snap-joint secured each to the other, and also held in placein a main casing, by a cast-iron head popularly known as a frost- Thishead has arms, flange bolts; whereby,vwhen water within the meterfreezes and theexpansion thereof develops sufiicient pressure, thefollowing results ensue:

Usually, (a) two or three of the arms fracture, permitting the head totilt outwardly; (b) the disc-casingis pushed down- Wardly, or it may beupwardly; and (0) the two sections of the disc-casing separated at theaforesaid snapoint. Hence, the interior parts are neither broken nordeformed, and the application of a new head restores the meter to itsformer operative condition. Follo mg the foregoing, this applicantapplied a system of springs, acting against a head," whereby, whenfrozen, the said headwas pressed outwardly was shifted and separated;then, the ice having melted, the

resilient springs automatically reset all of the functioning parts totheir normal position. j

The aforesaid system of frost protection has been universally adoptedwith but few, minor modifications; and it is indubitable that theindustrial savinghas amounted to of the meter shall be able to'test-pressure.

a very brief recitation engaged byare slightly millions of dollars.sible to still further hitherto attained.

However, it is yet pos- Thus, in regular practice, water meters aresubjected to a hydraulic test-pressure of say, 200 pounds to the squareinch; therefore, the frost bottom, or its equivalent element, mustpossess an additional margin of safety equal to not less than 25 to 50pounds per square inch to prevent fracture or deformation of the frostbottom itself under the test-pressure; and this necessitates that themain casing withstand an ice-pressure, without permanent deformation,some 25% to 40% greater than the As will shortly be pointed out, therecited objections are overcome or largely minimized by the presentinvention.

In the drawings, which constitute a part of this specification Figure 1-is a diagrammatic sketch-view of a disc water meter wherewith toelucidate the frost protection; and also showing the frost-bolt inplace, the scale of the latter being about full size, as applied to thehouse sizes of meters;

Figure 2 is a detached enlarged scale view of the bolt and its freeco-ordinating nut, the latter being in section;

Figure 3 is a revolved view of the aforesaid bolt and its nut;

Figure 4 is a plan view, projected from Figure 2';

Figure 5 is a detached section, still further enlarged, to betterillustrate a preferred form of the threads; and i ,Figure 6 is atransverse section of the bolt-rod in'a form best adapted forinexpensive manufacture.

The principle here employed maybe thus summarized: the employment ofclamping bolts and nuts of such form and material that, when subjectedto an adequate separating pressure, their threads will slip over eachother; and then, when free to doso, may automatically resume theirnormal engagement without rupturing or deforming the co-ordinatingsurfaces and parts.

7 The upper member 7 and the lowermember 8, denote the main casing of adisc water meter having flanges 9, 10, whilstthe disc casing, alsoformed of two members, 11, 12, has a snap-joint 13. The disc and itsballare partially denoted in dotted outaugment the advantages principle ofthe recited system of line. The disc chamber rests in a taperedside-bearing 14 in the lower portion of the main casin and is securedtogether, and to its seat l5,l y an overlapping portion of the uppersection of the main casing acting upon an interposed gasket, 16. Thus,when water within both the main casing and the 'disc casing freezes, ifthe two portions which constitute the main casing can separatesufficiently to allow for theme-expansion (about 8 ,per centum) the discchamber will becarried upwardly, and also slightly separated, withoutdamage thereto.

The benign action just mentioned is now attained by the resilientpronged bolt 17, and its free nut 18, Whose co-acting threads arepreferably of ratchet, or saw-tooth form,

their sloping surfaces, as 19, 'being .their thrust-resisting portions.It will doubtless already be apparent that when the stress,

, or pull, is sufficient to cause the wedge-like spring thebolt-prongsinwardly, as see dotted lines 20, 21, Figures 2 and 4, the; threadssurface of the nut-thread to sufficiently are thenfree to separate eachfrom the other, of them'to the extent of one of m ore pitchspaces, asthe case may be; Again, when free to do so, the prongs will snapback andthe co-ordinating threads will re-engage when the nut can be turned downor up, from the shifted position.

But to realize'the foregoing simple action,

the following details must be observed,"

namely: The bolt. at right angles to the prong-slot 22, must beflattened, as 23, 24,

and the sharp intersections should preferably be slightly rounded, as25, Figure 6..

The prong-slot should be of such a width that when the two upper edgescome togethei, as see Figures 2 and 4, the outer corners of thebolt-thread, 'at the flats of the bolt, will just clear the inner edgesof the nut-thread. Moreover, to avoid an undue width of the'prong-slot,the bore of the nut should betapered, as line 27 Figure 5, fiaringoutwardly from top to bottom; hence when the prongs are thrust inwardly,as to line 28, all of the edges of the nut-thread will be free to slipover those of the boltthread.

-' While the bolt and'its fixed head, 29, could be formed as one part,it is advantageous to apply a separate head, in thatthe bolt-portion maybe drawn in long rods to be thenafter threaded and'slotted, after whichthe prongs maybe heat-treated, or spring-temor by weakening the prongsat their roots,

servable as by drilling a-transverse hole thereat, 30,

tapped in a flange, whereby frost protection is readily applicable tolarge sizes of meters, which has not hitherto been the case.

Then, too, it is not necessary to provide, as in prior practice, anexcessive margin of safety in the main casing; for the prongbolts can beadapted to release at .a pressure equal toor even less than, that of theusual hydraulic test-pressure. This is feasible because, when the testpressure is being applied, which is usually but once in the life ofameter, wedges. may be inserted in'the prong-slots to prevent them fromfunctionmg 2 When the go point, as in 'a frost bot-- tom, is very high,the excessive pressure lowers the temperature of transformation into icewithin the meter; consequently, upon a sudden relief thereof, ice may beformed with explosive rapidity; but with a substantially lower go point,ice formation proceeds more slowly; it is less likely to cause internaldamage and the main casing of the meter may be considerably lighter.

It is not-without pertinency to here observe that the operation of thisfrost-bolt is an interesting exhibit of the principle that the frictionof rest is greater than that of the friction of motion; for, theprongthreads cling to the nut-threads without obeflection of the prongsuntil well up to the go-point and then, once started, they move inwardlywith but a moderate additional application of pressure although theside-tension of the prongs are becoming progressively greater.

The boltmay readily be formed with, say, four or six prongs; and such infact has been tested; but, the two-prong form is unquestionably thepreferable; for, among other reasons, a plurality of prong-slots soreduce the a gregate cross-sectional area of the prongs tiat the boltand its'nutmust be so increased in, their diameters as to be obect1onable or even commercially unfeasible. So, too, ordinary V-threadsmay be employed, the VVhitworth standard being the better; yet theratchet or saw-tooth form is distinctly the preferable in that, if nomore, and pitches being equal, the area of bearing surface is or may bethe greater. Theoretically, any form of thread is operative whoseresisting surface is disposed within an included an le of substantiallyless than between the vertical and the horizontal; but, in practice, themost effective results will be attained between a swing of about 30 to50.

A contingent advantage of this frost-bolteas es.

is that is serves to prevent needless and even destructive straining ofthe bolt and meterflanges. Thus, if the nut is excessively turned down.the prongs will spring inwardly and automatically release. in a normalapplication, all that needs be observed is to apply pressure until aslight inward movement of the prongs is observable, then fback-ofi?until they resiliently retrieve their normal position.

In sum, by thus utilizing ones earlier and well-proven separable systemof parts within awater meter, which may be of the disc b or other types,and applying this frostbolt to the exterior casing, or head, as the casemay be, a. frozen meter, or any part therein, or of the protectoritself, does not require removal; nor does an expert needs be called toread ust 1t; for, once the ice 1s melted, anyone can turn down the nutsto place.

'ing to that of said bore, all

What I claim is:

1. A water meter frost-bolt comprised in prongs whose free ends arethreaded and engaged by. a co-ordinating nut, the crosssectional form ofthe threads being like ratchet or saw-teeth and whose slopes serve asthe strain-resisting surfaces.

2. In water meters, a frost-bolt in the form oftwo flattened prongs, thecylindrical portions of their free ends being suitably threaded tonormally engage a continuous nut-thread, the inner bore of saidnut-thread are sprung inwardly to an angle correspondof thethrustresisting surfaces of the threads are simultaneously disengaged.

This specification signed on this the 9th 'day of February, A. D, 1923.

' JOHN THOMSON.

eing tapered; whereby, when the prongs

